When asked to explain her actions during the recent riots, one young woman claimed that she was "getting her taxes back". This may seem ludicrous, but it is strangely encouraging that she chose to describe her behaviour in such a political way. You cannot be totally isolated from wider society if you define your crime as a kind of tax rebate.

It is also a mistake to reject any relationship between the riots and the welfare system. As Wilkinson and Pickett demonstrated in their book The Spirit Level, there is good evidence that criminality and violence tend to increase with income inequality. What's more, the UK is the third most unequal developed country, after the US and Portugal.

The UK's tax system also plays a major role in this injustice. Many people do not realise that the poorest 20% of society pay more as a percentage of their income in taxes than any other group. The Office for National Statistics reported that in 2008-9 that the poorest 20% of the population paid 36.2% of their income in tax (including indirect taxes), while the top quintile paid 33.9%. Recent increases in VAT and other duties have since made the situation of the poorest even worse.

The poor also pay the highest levels of marginal tax – the tax on the next pound you earn. In fact, for many relying on benefits the effective marginal tax rate is often 100%. The government now hopes to reduce this tax rate to less than 80%, but its strategy for funding this change is to make even deeper cuts in benefits to disabled people and those who do not work. So it seems it is the poor who will have to fund this reform of the tax system.

It is not just the tax system in relation to benefits that is unfair. The way taxes are used is also unfair. In a recent publication from the Centre for Welfare Reform – Women at the Centre – we found that those women who are among the poorest in society are often swimming in a toxic cocktail of multiple and reinforcing needs: poverty, domestic violence, sexual abuse, poor mental health and chronic health conditions.

Yet public services were not organised to focus on these women; instead the best support has come from a community-based organisation that is led by local women and which receives minimal state support.

It is not just vulnerable groups who do not get a fair deal from the current welfare state; sometimes it is whole geographical areas. John Gillespie recently described how public services can effectively be given up in estates that are seen as too difficult. It is only when local people take back control into their own hands that we have started to see an end to cycles of deprivation and neglect and a new partnership between local people and public services.

It is striking to compare the student riots with the summer riots. The student riots were not so violent and they clearly focused on protecting the legitimate interests of the educationally gifted who want a university education. Moreover, politicians and journalists did debate these issues. In comparison, the summer riots have been deadly, violent and largely inarticulate. There has been no clear voice of protest and no real debate on policy.

But surely it valid to ask whether the summer rioters might also sometimes wonder whether there is anyone interested in protecting their interests, helping them find work, subsidising their education or personal development, in the same concerted way that society seeks to protect and develop its students.

"No taxation without representation" was the slogan of the American War of Independence and it is a stern reminder that the legitimacy of a taxation system is measured, not just by how fair taxes seem, but also by whether you feel you played any part in setting them. But in the UK, it is no longer clear who represents the poor. It does not seem to be the Labour party, for the left has found that it can only win elections if it focuses primarily on the interest of middle-earners, and it has found it increasingly difficult to keep the interests of them connected to the interests of the poor.

None of this justifies violence, theft and murder. The riots were wrong. If you are angry about injustice then you can get involved in making things better. But if we refuse to face the relationship between injustice and social unrest we will find that riots and many other social problems will continue to haunt us.